Thousands of Thai riot police faced off against anti-government demonstrators in Bangkok Friday as they attempted to seize sites occupied by protesters for months, reports CNN.

Security forces only succeeded in narrowing the areas held by protesters in some parts of the city, but vowed to return to continue their efforts Saturday. The stand-offs passed without serious violence, although a journalist sustained minor injuries when a protester near Government House threw a firecracker.

Demonstrators opposed to the government of Prime Minister Yingluck Shinawatra have been camped out since November at sites including Government House -- the office of the prime minister and appointed cabinet ministers -- and the government complex in the Chaengwattana area of Bangkok's suburbs.

While security forces succeeded in seizing only some of the territory held by protesters, he said they would be back tomorrow.

"We have withdrawn our forces and will go back there again tomorrow," said Paradon. "We were there to express our seriousness that we have to retake the area, (or) at least open up the roads for public."

He said he did not expect events to turn violent, saying his approach was to attempt negotiations before sending in teams to retake the area.

Protesters have been calling for the ouster of Yingluck, whom they allege is a puppet of her billionaire brother, the deposed, exiled former Prime Minister Thaksin Shinawatra. The protests were sparked in November by her government's attempt to pass an amnesty bill, that would have paved the way for her brother's return to the political fray in earnest.